In the existing products for kitchen & bathroom and pipes, most of structures having a single button to switch between two functions include a long strip shaped seesaw structure and a structure similar to a ball-point pen. Even though the seesaw structure can realize a memory function, it is unattractive and inconvenient to operate, and needs more space to accommodate the button at the location where this structure is applied. The structure of ball-point pen may have an aesthetic appearance. Further, it is convenient to switch, and require less space for the button. However, this structure cannot realize the memory function.